Dragons are the first really powerful troop you get and the one I use a lot in Clan Wars. Dragons have a lot of health so, whilst they
are susceptible to air defenses, they can take quite a few hits before they are destroyed. A pure dragon rush is where you have only dragons, you drop them at one end or corner of
a base and use rage spells as they get near air defenses or clan castle troops. Alternates are to look for bases where the air defenses are relatively exposed and put the dragons
near them so they go after them first, hopefully taking them out before they get destroyed. If there is an air defense in the center, lightning spells can be used to remove one of the
Dragon attacks are very effective for players at Town Hall 7 to use against other Town Hall 7's in Clan Wars. At that Town Hall, there are only two air defenses and you can normally
get to one or both of them fairly easily. The biggest drawback of this strategy is the cost. 10 level 2 dragons are going to set you back 300,000 resources, so this is not
a strategy you want to use when farming as it is very difficult to recoup your cost. I generally put some balloons in my army along
with the dragons in order to target specific defenses. You can drop the dragons in first and they will attrack the fire from the air defenses. You can then put balloons in
behind the dragons and they will go straight to the defenses and will hopefully be protected from attack.
Here's an extract from a video I put together on one of our Clan Wars that features dragon attacks.